Wood chips of varying sizes are hauled using road trailers. One version of these road trailers, known as chip trains, includes two trailers hauled behind a tractor unit; a lead trailer (nearest the tractor) and a pup trailer. To maximize the hauled load, it is desirable for chip trains to be as light-weight and as large as possible. This can be achieved in part by designing the trailers to meet the maximum allowable road limits for width, height, and length. Use of lightweight construction material, such as aluminum, is also possible. When loaded, the wood chips often heap higher than the height of the trailer, an allowable method to fit additional chips in many jurisdictions.
The tops of the chip trailers are often open to facilitate loading. Loading is typically done via a front-end loader or by driving under a hopper filled with chips. To unload the chips, the entire chip train and tractor unit can be driven onto a hydraulic tipper. This tipper then raises the chip train and tractor to a steep incline. The front and rear of the pup trailer, and the rear of the lead trailer, are composed of doors that swing open. These doors are unlatched when on the tipper, and the chips flow through both trailers into a pit below the tipper.
Loads should be retained when driving and chips easily blow out the top of the trailer. One common approach is to have a tarp manually drawn across the top of each trailer before transporting chips. This is accomplished by climbing a ladder to a small platform between the trailers. Manual tarping is inherently dangerous, as the operator stands on a small platform approximately 3 meters off the ground in possibly difficult environmental conditions while attempting to draw a tarp across a heaped load. Injuries, often serious, can occur. It also takes a significant amount of time to accomplish the manual tarping and untarping of each trailer.
Due to the size and weight constraints of chip trains, the large doors, and the nature of wood chips, mechanically assisted tarping solutions for this application are challenging, and existing solutions are not fully satisfactory.
Therefore there is a need for an apparatus for covering a container load, such as woodchips of a chip train, or other bulk materials, that is not subject to one or more limitations of the prior art.
This background information is provided to reveal information believed by the applicant to be of possible relevance to the present invention. No admission is necessarily intended, nor should be construed, that any of the preceding information constitutes prior art against the present invention.